Monosaccharides are the simplest form of a large and diverse group of organic compounds called carbohydrates. They are sweet, water soluble substances that contain more than one hydroxyl group (OH) and a carbonyl group (C {double bond} O). They are either polyhydroxy aldehydes or ketones depending on whether the carbonyl group is formed from a terminal carbon (aldoses), or not (ketoses). They are grouped by the number of carbon atoms they contain; trioses have three, tetroses four, pentoses five, and hexoses six. The smallest monosaccharides are the two forms with a three carbon skeleton: glyceraldehyde and dihydroxyacetone. Pentoses and hexoses are most common, but monosaccharides may contain as many as nine carbons. They are named by combining a prefix that may designate the number of carbons in the molecule or some other discriptive feature, and a generic suffix -ose.

Important pentoses include xylose, and arabinose, both of which...